It sounds like a spy novel. A former CIA case officer joins a cabal of pro-Russian rebels attempting to kill the prime minister of a small Balkan country. The coup fails, the officer returns to the US -- and now authorities in the Balkans want the former spy for questioning.

Last week Montenegro announced it is seeking extradition of the retired US spy, Joseph Assad, for his role in an attempted coup there in 2016. If the allegations are true, this story has a twist worthy of an airport-bookstore thriller: The US and Russia may be rivals, but when it comes to Montenegro, they are secret collaborators.

Unfortunately -- at least for a spy novelist -- the charges against Assad appear to be thin. In an interview last weekend in Washington, Assad told me he knows nothing about the attempted coup and doesn’t understand why the US government has not put a stop to all of this.

Assad was in Podgorica, Montenegro’s capital, in the week leading up to the parliamentary election on Oct. 16, 2016. (The alleged coup was foiled on Election Day.) He was there, he said, to provide security advice for an Israeli political consultant who was advising an opposition coalition.

Two of the three parties in that coalition did not support Montenegro’s accession into NATO -- a position that accorded with Russia’s strategic plans. But that’s not the same as saying Assad (or the consultant, Aron Shaviv) was working for the Russians.

Now Assad says he is being set up by Montenegrin prosecutors to testify about a coup attempt he knows nothing about. Their real goal, he suspects, is to get “a former CIA official to say derogatory things about the opposition.” But he has never met the alleged plotters, he said, “and, frankly, I don’t care about them. I was in Montenegro for Shaviv.”

Some background: Montenegro, population approximately 640,000, formally joined NATO in 2017. The US supported both Montenegro’s NATO membership and its independence from Serbia 11 years earlier. The Russians opposed both. Last month, Trump made headlines when he said that defending Montenegro from a Russian attack could cause World War III. Meanwhile, pro-NATO lawmakers such as Sen. John McCain have called attention to the Russian role in the attempted coup to make the case for vigilance in defending NATO allies from Moscow’s predations.

McCain’s fears are not unfounded. The Russians have increased their political meddling in Europe in recent years, and Montenegrin prosecutors have amassed some evidence that there was a coup attempt. They have fingered two Russian military intelligence officers and linked them to Russian special operations forces who had amassed on the Serbian-Montenegrin border the night before the 2016 election.

And Montenegro’s defenders say prosecutors would not seek Assad’s extradition unless they had a strong case. “Why would they casually jeopardize, on behalf of an unsubstantiated conspiracy theory, their most important foreign relationship?” asked Randy Scheunemann, a former adviser to Montenegro on its NATO accession. “It doesn’t make any sense.”

Granted, the case could make more sense if Montenegrin prosecutors release more information, and they may yet do so. That said, the public evidence against Assad is scant.

One known allegation is that Assad prepared an exfiltration plan for the coup plotters. Assad says what he prepared was a contingency plan for his client in case of an emergency -- basic advice like where to meet if phone service is shut down, or whether to buy a plane ticket for Albania or Croatia. Hardly top-secret stuff.

Assad’s client backs up Assad’s story. As the campaign became more competitive, Shaviv said, his employees started experiencing official harassment -- pulled over on the highway, for example, and being detained at the airport. Assad was hired “to provide me and my team risk assessments for our personal security,” Shaviv told me.

Curiously, Shaviv has not been summoned for questioning by the Montenegrin special prosecutor, even though he has much closer ties to the opposition coalition alleged to have plotted the coup.

Shaviv is not the only one with doubts about the prosecutor’s story. Daniel Hoffman, a former CIA station chief in Moscow who worked with Assad in the Middle East in the 2000s, told me he suspects the charges against Assad stem from a larger Russian disinformation campaign. “The Russian interest is to tear apart Montenegro’s civil society,” he said. “I would not put it past the Russians to embellish Joseph’s role to make it appear he was providing strategic guidance to an anti-NATO, pro-Russian opposition party.”

“I can’t imagine him doing anything like this,” Hoffman added. “This isn’t the guy I know, with whom I served.” Other former CIA officials I talked to concurred with that assessment of Assad, and it’s easy to see why. A naturalized US citizen who was born in Egypt, Assad devoted most of his career to fighting jihadists in the Middle East. He continued this work after he retired from the agency. Before joining the CIA, Assad worked as a researcher for Freedom House, documenting the harassment and abuse of dissidents in Egypt.

Assad’s fate now lies with the State Department, which rules on extradition requests. The US has an extradition treaty with the former Yugoslavia, which included Montenegro. It does not have a formal treaty with Montenegro. Assad’s lawyer, Vince Citro, said he will oppose any extradition request, in part because US courts have no authority to review secret evidence.

For his part, Assad is clear about any efforts to destabilize or undermine democracy. “I think the Russians are up to no good,” he told me over the weekend. “They work against our interests, they assassinate opposition figures, they are meddling in countries around the world,” he said. “I would never work with them.”